Suture locking device

ABSTRACT

A device for locking a suture in place without the need for tying knots once the suture is placed within tissue is provided. The device comprises an anchor having a cannula and a locking mechanism for securing the suture within the cannula.

This application is a continuation of U.S. patent application Ser. No.11/354,770, filed on Feb. 15, 2006, now U.S. Pat. No. 7,846,181, whichis a continuation of U.S. patent application Ser. No. 10/186,805, filedon Jul. 1, 2002, now U.S. Pat. No. 7,033,380, which is a divisional ofU.S. patent application Ser. No. 09/883,691, filed Jun. 18, 2001, nowU.S. Pat. No. 6,432,123, which is a divisional of U.S. patentapplication Ser. No. 09/474,416, filed Dec. 29, 1999 now U.S. Pat. No.6,319,271, which claims priority under 35 U.S.C. §119(e) to U.S.Provisional Application No. 60/114,170, filed Dec. 30, 1998, each ofwhich is expressly incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to a device for locking a suture in vivo,more particularly to a device for locking a suture in vivo without theneed for tying knots once the suture is placed within tissue. Thepresent invention also relates to a method for using such a device toapproximate tissue and to lock the suture in place.

BACKGROUND AND SUMMARY OF THE INVENTION

It is known in the art to approximate damaged or torn tissue by use of asuture. In many instances, the suture is looped through tissue, and thetwo ends are then secured together. Prior art methods for securing asuture include tying knots. Other methods include providing a filamenthaving various protruding portions and securing the filament against oneof those protruding portions. See, e.g., U.S. Pat. No. 5,520,691,incorporated herein by reference. Still other prior art methods includecompressing the suture between a cylinder/piston wall interface. See,e.g., U.S. Pat. No. 5,630,824, incorporated herein by reference. Suchsutures may be used to approximate damage in soft tissue or to attachsoft tissue to bone.

The present invention provides a suture locking device that relies onfrictional forces. In one embodiment, a suture is passed through ananchor having a tapered or stepped cannula. The suture is then passedthrough tissue, may be passed through or around a second anchor locatedon the opposite side of the defect, and looped back through the cannula.One end of the suture may be provided with a knot or bead. As thesurgeon pulls on the second end, the knot or bead enters the cannula,pulls the two anchors toward each other, then both strands wedge tightlyin the cannula. In an alternative embodiment, instead of a knot or bead,a slip knot is provided on the first end. The second end may be threadedthrough the slip knot. Again, as the surgeon pulls on the second end,the knot will enter the tapered or stepped cannula, pull the two anchorstogether, and wedge both strands tightly within the cannula.

In another embodiment of this invention, a locking ring is used tosecure the sutures to the anchor. The anchor may be provided with asplit section and the suture would pass through this split section. Thelocking ring may be of either the push-type or the pull-type, and whenengaged, the locking ring would force the portions of the split sectiontogether, thus wedging the split section together and locking the suturestrands in place. The split section may be provided with teeth to gripthe suture better.

In another embodiment, the suture may be secured with a snap grooveprovided on the anchor. As with the locking ring arrangement, the anchorwould be provided with a split section. A tooth on one section is sizedand shaped to mate with a groove on the other section. When the tooth issnapped into the groove, the suture strands would be locked into place.

An additional embodiment may employ a wedge design. In such a design,the anchor may be provided with a cylindrical cannula, and a wedge wouldbe provided to fit tightly within the cannula. The wedge itself may bepartially cannulated to aid in insertion, but the suture would also, inpart, pass along the exterior of the wedge, so that frictional forceswould secure the suture between the wedge and the inside of the cannula,in order to lock the suture in place.

Alternatively, the suture locking device may comprise laminated sheets.Slits in the laminated sheets would allow the suture to pass in onedirection with little resistance. However, the sheets would be designedto lock on the suture when the suture is pulled in the reversedirection. Thus, the surgeon could pull on the suture to tighten it, andthe suture would remain locked in place.

Some embodiments of the present invention are described for situationsin which the suture is looped through tissue, and two ends of the suturemust be secured. Other embodiments are described in which each end ofthe suture strand is secured independently. It will be understood thatthe invention may be employed in situations involving a single strand orwith multiple suture or filament strands. Also, it will be understoodthat the scope of this invention is not limited specifically to securingtwo ends of a suture within one locking mechanism.

The anchor may be made of biocompatible material such as stainlesssteel, titanium, cobalt chrome, and polyethylene. Preferably,biodegradable materials may also be used, including poly lactic acid andpoly lactic-glycolic acid. Other biodegradable materials are known. See,e.g., U.S. Pat. No. 4,976,715, hereby incorporated by reference. Thesuture may be made of resorbable or non-resorbable material, as areknown in the art.

Therefore, in one embodiment of the present invention, a device isprovided for locking a suture in place, the device comprising an anchorhaving a cannula, the cannula for receiving a suture, and a lockingmechanism for locking the suture in place. The locking mechanism maycomprise a bead, knot, or wedge sized to wedge within the cannula or thelocking mechanism may comprise a locking ring. The cannula may becylindrical, tapered, or stepped.

In another embodiment of the present invention, a device is provided forlocking a suture in place, the device comprising an anchor having acannula and a locking mechanism. The cannula is for receiving thesuture, and the locking mechanism is for locking the suture within thecannula. The locking mechanism may comprise a locking ring or a snapgroove.

In still another embodiment of the present invention, a device forlocking a suture in place is provided, comprising an anchor having afront edge and a rear edge, the anchor having a cannula extending fromthe front section to the rear section, and a locking mechanism. In thisembodiment, the suture comprises a first end and a second end, thesuture extending through the cannula of the anchor from the rear edge tothe front edge, through a portion of tissue, and extending back throughthe cannula from the front edge to the rear edge, the second endprotruding from the rear edge of the suture. The locking mechanismcomprises a bead located at the first end of the suture, and the beadsized to fit snugly within a portion of the cannula. Pulling the secondend of the suture causes the bead to travel toward the front edge of theanchor and to wedge within the portion of the cannula, thereby lockingthe suture in place.

Additional features of the present invention will become apparent tothose skilled in the art upon consideration of the following detaileddescription of preferred embodiments exemplifying the best mode ofcarrying out the invention as presently perceived.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a locking device of this invention,in which the locking device comprises an anchor with a tapered cannulaand a suture with a bead, shown in combination with a second anchor;

FIG. 2 is a cross-sectional view of the anchor of FIG. 1, with thesuture in locked position;

FIG. 3 is similar to FIG. 2, except that the cannula is stepped ratherthan tapered;

FIG. 4 is similar to FIG. 1, except that a slip knot replaces the bead;

FIG. 5 is a cross-sectional view of another embodiment of thisinvention, in which the suture locking device comprises a pull lockingring in combination with a cannulated anchor;

FIG. 6 is similar to FIG. 5, except showing the device in a lockedposition;

FIG. 7 is similar to FIG. 5, except showing a device with a push lockingring;

FIG. 8 is similar to FIG. 7, except showing the device in a lockedposition;

FIG. 9 is a cross-sectional view of an embodiment of this inventionemploying a snap lock design;

FIG. 10 is a cross-sectional view of still another embodiment of thisinvention which employs a wedge design;

FIG. 11 is a perspective view of an additional embodiment of thisinvention, employing a laminated sheet design;

FIG. 12 is a cross-sectional view of FIG. 11, along line 12-12; and

FIG. 13 is a cross-sectional view of a meniscus of a knee, showing adefect approximated by a suture that is locked into position by usingtwo locking devices of FIG. 11.

FIG. 14 is a cross-sectional view of a meniscus of a knee, showing adefect approximated by a suture that is locked into position by alocking device and an anchor.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows generally a suture locking device of this invention in acombination as the device may be employed. In the illustrativeembodiment, a suture 40 passes through a cannula 22 in an anchor 20. Thesuture loops through or around a second anchor 80, and then returnsthrough cannula 22. In use, anchor 20 and second anchor 80 may belocated on opposite sides of a soft tissue defect (not shown), andsuture 40 may be used to pull the defect together. Alternatively, secondanchor 80 may be located within or beyond a portion of bone (not shown),and anchor 20 may be used to attach soft tissue to the bone. Otherapplications are also possible.

As shown, second anchor 80 is provided with two holes 82, 84. Suture 40extends from first anchor 20 to second anchor 80, loops through firsthole 82 and returns through second hole 84 back to first anchor 20.Alternatively, second anchor 80 may be provided with one hole throughwhich suture 40 passes before returning to first anchor 20. In otherembodiments, second anchor 80 may be provided with a singularcannulation lengthwise with the suture 40 extending therethrough, or thesecond anchor 80 may be provided without any holes, and the suture 40may merely loop over second anchor 80. In some situations, a secondanchor may not be necessary, and suture 40 simply loops over or throughtissue.

In the embodiment shown in FIG. 1, the anchor 20 is configured to burypartially or totally into tissue, for use in tissue repair whereinterference with the tissue surface is not desirable. Thisconfiguration may be desirable for use on surfaces such as the innersurface of the meniscus of the knee, where a protruding anchor mayinterfere with joint articulation. However, as illustrated in FIGS.10-13, anchors which are configured to abut, without entering, tissueare also within the scope of this invention. The combination illustratedin FIG. 1 is meant merely as an example of a suture/anchor combinationthat may be locked with the suture locking device of this invention.

Referring still to FIG. 1, suture 40 is provided with a first end 42 anda second end 44. As shown, first end 42 is provided with a bead 46, andthe cannula 22 is tapered. As the surgeon pulls on the second end 44 ofsuture 40, the bead 46 enters the cannula 22. With continued pulling,the bead 46 pulls anchor 20 toward second anchor 80, for example, toclose a defect in tissue or to secure soft tissue to a bone. When anchor20 is fully seated, bead 46 wedges into cannula 22, and bead 46 securessecond end 44 within the cannula 22.

FIG. 2 illustrates the anchor 20 of FIG. 1 after the suture 40 has beenpulled tight and locked into place. FIG. 3 illustrates an alternativeembodiment wherein the cannula 22 is stepped, rather than tapered. Aswith the embodiment illustrated in FIG. 2, when suture 40 is pulledtight, the bead 46 locks the suture 40 in place. Bead 46 may bepermanently affixed to suture 40 in any number of ways, as are known inthe art. Alternatively, suture 40 may be manufactured with bead 46 as aprotuberance integral with the suture filament. Also, bead 46 may be aknot in suture 40 of sufficient size to lock suture 40 in place.

Another embodiment is illustrated in FIG. 4. The first end 42 of suture40 is provided with a slip knot 48. As with the embodiment shown in FIG.1, the anchor 20 is provided with a cannula 22 that may be tapered orstepped. Preferably, second end 44 is fed through loop 49 of slip knot48, and the loop 49 may be tensioned slightly. As the surgeon pulls onthe second end 44, slip knot 48 will travel distally along the secondend 44, until slip knot 48 begins to push the anchor 20 toward thesecond anchor 80. As with the bead 46 of FIG. 1, slip knot 48 wedges incannula 22, locking the suture in place.

FIGS. 5-8 relate to embodiments employing locking rings. FIGS. 5 and 6involve a pull locking ring with FIG. 5 illustrating the open positionand FIG. 6 illustrating the locked position. As illustrated in FIGS. 5and 6, anchor 20 is provided with cannula 22. Preferably, rear section24 of anchor 20 is split into first and second rear portions 26, 28, todefine split gap 30. An annular locking ring 70 is provided aroundmiddle section 25. Once anchor 20 and suture 40 are properly positioned,locking ring 70 may be pulled in the direction away from front 23 andtoward rear 24 of anchor 20. First and second rear portions 26, 28 arecompressed together by locking ring 70, thus securing suture 40 within.Teeth 32 may be provided to insure secure gripping of suture 40. Asillustrated in FIG. 6, a groove 72 on locking ring 70 may be providedfor seating on tip 29, to secure locking ring 70 in place.

Referring specifically to FIG. 5, as illustrated, in the open positionlocking ring 70 sits between front section 23 and rear section 24. Aninsertion tool (not shown) may engage a recess or protuberance (notshown) in rear surface 74 of the locking ring 70, in order to aid inpulling locking ring 70 to the closed position, as illustrated in FIG.6. Also, because middle section 25 of anchor 20 provides a recess inwhich locking ring 70 sits while in the open position, locking ring 70need not be physically connected to anchor 20. Alternatively, afrangible portion (not shown) may be used to secure locking ring 70 toanchor 20. The frangible portion would be broken as locking ring 70 ispulled back to the closed position.

FIGS. 7 and 8 illustrate an embodiment of a suture locking deviceemploying a push locking ring. FIG. 7 illustrates the push locking ring60 with the device in the open position. As with the embodiment shown inFIGS. 5 and 6, anchor 20 may be provided with a rear section 24 whichhas been split into first and second rear portions 26, 28, defining slitgap 30. A locking ring 60 is disposed around rear section 24. Whenlocking ring 60 is pushed toward the front section 23 of anchor 20, thelocking ring compresses rear portions 26 and 28 together, locking suture40 therebetween. As with the pull locking ring embodiment illustrated inFIGS. 5 and 6, the anchor 20 may be provided with teeth 32, in order tobetter secure suture 40. Once locking ring 60 is in the locked position,lip 34 may be provided to lock edge 62 in place and restrain lockingring 60 from moving back to the open position. As illustrated, edge 62is recessed from rear surface 64. However, edge 62 may protrude from orbe contiguous with rear surface 64.

Still referring to FIGS. 7 and 8, rear surface 64 of locking ring 60 maybe provided with a recess (not shown) for use with an insertion tool(not shown). Also, locking ring 60 may be connected to anchor 20 by afrangible portion 66. When force is placed on locking ring 60, thefrangible portion 66 would break, and locking ring 60 would slip intothe locked position shown in FIG. 8. An alternative location for thefrangible portion is illustrated as frangible portion 66 a, althoughmany other locations are possible. Alternatively, locking ring 60 may beconnected by a tether (not shown). In still another alternativeembodiment, locking ring 60 need not be physically connected to anchor20, and locking ring 60 may be inserted simply by pushing it alongsuture 40.

FIG. 9 illustrates an embodiment of this invention which employs a snapgroove. As with the locking ring embodiments, rear section 24 of anchor20 is split into first and second portions 26, 28, defining split groove30. A tooth 36 is provided on first portion 26, while a matching groove37 is provided on second portion 28. Suture 40, which has been insertedthrough cannula 22, also extends between tooth 36 and grove 37. Whentooth 36 is snapped into groove 37, suture 40 is captured therebetweenand becomes locked into place. It is understood that, while a singulartooth and groove are illustrated in FIG. 9, embodiments employingmultiple teeth and grooves are within the scope of this invention.

A wedge design may be used, as illustrated in FIG. 10. In thisembodiment, anchor 20 is provided with cannula 22. A wedge 50 is shapedto fit snugly within cannula 22. Wedge 50 may be partially cannulated,as illustrated with cannulae 52. As illustrated, suture 40 may bethreaded through cannula 22 of anchor 20 and then through cannulae 52 ofwedge 50. As illustrated, suture 40 also passes over arch 54. Withtension on suture 40, wedge 50 may be pushed into cannula 22. Suture 40then becomes locked between arch 54 and the inner wall of cannula 22.While the illustrated cannula 22 and wedge 50 are cylindrical, it willbe understood that other shapes may be used. It is also understood thatcannulae 52 are provided only for ease of insertion, and that wedge 50may be provided without cannulations.

Still referring to FIG. 10, the anchor 20 as illustrated may be used inapplications where front section 23 of anchor 20 is to remain flush withthe tissue surface. However, it is understood that a wedge suturelocking device may be used in various applications with various anchordesigns.

FIGS. 11-12 illustrate another embodiment of a locking device of thisinvention. Locking ring 90 is constructed from a series of laminatedsheets 92. The laminated sheets may be bonded or welded together alongthe circumference 95 of locking ring 90. Slits 93 may be providedthrough each of the laminated sheets 92. An aperture 94 is defined asthe intersection of slits 93. Aperture 94 allows suture 40 to passthrough locking ring 90. As can be seen in FIG. 12, the laminated sheetsare constructed such that if suture 40 is pulled in the directionindicated by the arrow, suture 40 may pass freely with littleresistance. However, if suture 40 is pulled in the opposite direction,slits 93 close as laminated sheets 92 start bending back uponthemselves. Thus, suture 40 is locked into position.

FIG. 13 illustrates two locking rings of FIGS. 11 and 12 used to repaira defect 101 in a meniscus 100. As illustrated, locking ring 90 a islocated at the inner surface 102 of meniscus 100, while locking ring 90b is located at the outer surface 103 of meniscus 100. Locking rings 90a and 90 b secure suture 40 in place, thereby approximating the defect101. It should be understood that FIG. 13 is illustrative of just oneexample of the present invention. Any of the embodiments could be usedto approximate such a defect. FIG. 14 is illustrative of another exampleof the present invention. The various embodiments of this invention maybe used to secure one or multiple sutures in a wide variety of uses.

Although the invention has been described in detail with reference tocertain preferred embodiments, variations and modifications exist withinthe scope and spirit of the invention as described and defined in thefollowing claims.

1. A method for repairing a defect in a soft tissue, the methodcomprising: positioning a first anchor on a first portion of theexternal surface of the soft tissue; positioning a second anchor on asecond portion of the external surface; coupling a first end of a sutureto the first anchor; passing the suture from a first side of the defectto a second side of the defect; passing the suture in a first directionthrough a first aperture defined in the second anchor; passing thesuture in a second direction opposite the first direction through asecond aperture defined in the second anchor; and tensioning the suturesuch that the first side of the defect and the second side of the defectare moved toward each other, wherein (i) the suture traverses the defectat least twice, and (ii) the suture includes a second end not coupled tothe first anchor such that the suture extends between the first anchorand the second anchor only once.
 2. The method of claim 1, furthercomprising locking the suture in place relative to the first anchor andthe second anchor.
 3. The method of claim 2, wherein locking the suturein place between the first anchor and the second anchor comprisesoperating a locking mechanism of the first anchor to lock the suture inplace relative to the first anchor.
 4. The method of claim 2, whereinlocking the suture in place between the first anchor and the secondanchor comprises (i) operating a first locking mechanism of the firstanchor to lock the suture in place relative to the first anchor and (ii)operating a second locking mechanism to lock the suture in placerelative to the second anchor.
 5. The method of claim 1, whereincoupling a suture to the first anchor comprises threading the suturethrough an aperture defined in the first anchor and an aperture definedin the second anchor.
 6. The method of claim 1, wherein tensioning thesuture comprises pulling the suture through at least one of the firstanchor and the second anchor.